Method and apparatus for improving mobile-terminated call set-up performance

Abstract

An apparatus and method for improving mobile-terminated call set-up performance comprising triggering an inter-radio access technology (IRAT) transition from a source cell to a target cell, remembering the deterministic timing of a plurality of paging occasions in the source cell, and using the deterministic timing for checking at least one paging channel in the source cell during transition to the target cell and before starting to monitor at least one paging channel in the target cell.

1. A method for improving mobile-terminated call set-up performance comprising:
 triggering an inter-radio access technology (IRAT) transition from a source cell to a target cell; 
 storing, in a memory of an electronic device, information regarding scheduled times of a plurality of paging occasions in the source cell; and 
 checking, at the scheduled times, at least one paging channel in the source cell during transition to the target cell and before starting to monitor at least one paging channel in the target cell. 
 
     
     
       2. The method of  claim 1  further comprising collecting system information of the target cell to allow successful inter-radio access technology transition. 
     
     
       3. The method of  claim 2  further comprising determining that the system information of the target cell has been collected. 
     
     
       4. The method of  claim 3  further comprising performing a mobility information update on the target cell including one or more of Location Area update in GSM, GPRS, UMTS or LTE; Routing Area update in GPRS, UMTS or LTE; UTRAN Routing Area in UMTS; or Tracking Area in LTE when it has been determined that the system information of the target cell has been collected. 
     
     
       5. The method of  claim 4  further comprising starting to monitor the at least one paging channel in the target cell. 
     
     
       6. The method of  claim 1  further comprising checking for a page in the source cell at the schedules times. 
     
     
       7. The method of  claim 6  further comprising answering the page in the source cell. 
     
     
       8. The method of  claim 6  further comprising determining that the quality of the source cell is above a threshold. 
     
     
       9. The method of  claim 8  further comprising answering the page in the source cell when it has been determined that the quality of the source cell is above the threshold. 
     
     
       10. The method of  claim 8  further comprising performing a mobility information update on the target cell when it has been determined that the quality of the source cell is not above the threshold. 
     
     
       11. The method of  claim 10  further comprising answering the page in the target cell. 
     
     
       12. The method of  claim 8  wherein the threshold is a value of one of the following: a received signal level, a received signal-to-noise ratio, a received interference power, a total received power, a path loss, a bit error rate, a frame error rate or a packet loss rate. 
     
     
       13. The method of  claim 1  further comprising comparing a target cell signal quality with a source cell signal quality to determine triggering the inter-radio access technology (IRAT) transition. 
     
     
       14. The method of  claim 13  wherein the target cell signal quality is higher than the source cell signal quality. 
     
     
       15. The method of  claim 14  wherein the target cell signal quality is higher than the source cell signal quality for a continuous time interval of at least 5 seconds. 
     
     
       16. The method of  claim 1  wherein the source cell is within a 2G coverage area and the target cell is within a 3G coverage area. 
     
     
       17. A user equipment comprising a processor and a memory, the memory containing program code executable by the processor for performing the following:
 triggering an inter-radio access technology (IRAT) transition from a source cell to a target cell; 
 storing information regarding scheduled times of a plurality of paging occasions in the source cell; and 
 checking, at the scheduled times, at least one paging channel in the source cell during transition to the target cell and before starting to monitor at least one paging channel in the target cell. 
 
     
     
       18. The user equipment of  claim 17  wherein the memory further comprising program code for collecting system information of the target cell to allow successful inter-radio access technology transition. 
     
     
       19. The user equipment of  claim 18  wherein the memory further comprising program code for determining that the system information of the target cell has been collected. 
     
     
       20. The user equipment of  claim 19  wherein the memory further comprising program code for performing a mobility information update on the target including one or more of Location Area update in GSM, GPRS, UMTS or LTE; Routing Area update in GPRS, UMTS or LTE; UTRAN Routing Area in UMTS; or Tracking Area in LTE when it has been determined that the system information of the target cell has been collected. 
     
     
       21. The user equipment of  claim 20  wherein the memory further comprising program code for starting to monitor the at least one paging channel in the target cell. 
     
     
       22. The user equipment of  claim 17  wherein the memory further comprising program code for checking for a page in the source cell at the scheduled times. 
     
     
       23. The user equipment of  claim 22  wherein the memory further comprising program code for answering the page in the source cell. 
     
     
       24. The user equipment of  claim 22  wherein the memory further comprising program code for determining that the quality of the source cell is above a threshold. 
     
     
       25. The user equipment of  claim 24  wherein the memory further comprising program code for answering the page in the source cell when it has been determined that the quality of the source cell is above the threshold. 
     
     
       26. The user equipment of  claim 24  wherein the memory further comprising program code for performing a mobility information update on the target cell when it has been determined that the quality of the source cell is not above the threshold. 
     
     
       27. The user equipment of  claim 26  wherein the memory further comprising program code for answering the page in the target cell. 
     
     
       28. The user equipment of  claim 24  wherein the threshold is a value of one of the following: a received signal level, a received signal-to-noise ratio, a received interference power, a total received power, a path loss, a bit error rate, a frame error rate or a packet loss rate. 
     
     
       29. The user equipment of  claim 17  wherein the memory further comprising program code for comparing a target cell signal quality with a source cell signal quality to determine triggering the inter-radio access technology (IRAT) transition. 
     
     
       30. The user equipment of  claim 17  wherein the source cell is within a 2G coverage area and the target cell is within a 3G coverage area. 
     
     
       31. The user equipment of  claim 17  wherein the source cell is within a GSM coverage area and the target cell is within a LTE coverage area. 
     
     
       32. The user equipment of  claim 17  wherein the source cell is within a GSM/GPRS/EDGE coverage area and the target cell is within a UMTS coverage area. 
     
     
       33. A wireless device for improving mobile-terminated call set-up performance comprising:
 means for triggering an inter-radio access technology (IRAT) transition from a source cell to a target cell; 
 means for storing information regarding scheduled times of a plurality of paging occasions in the source cell; and 
 means for checking, at the scheduled times, at least one paging channel in the source cell during transition to the target cell and before starting to monitor at least one paging channel in the target cell. 
 
     
     
       34. The wireless device of  claim 33  further comprising means for collecting system information of the target cell to allow successful inter-radio access technology transition. 
     
     
       35. The wireless device of  claim 34  further comprising means for determining that the system information of the target cell has been collected. 
     
     
       36. The wireless device of  claim 35  further comprising means for performing a mobility information update on the target cell including one or more of Location Area update in GSM, GPRS, UMTS or LTE; Routing Area update in GPRS, UMTS or LTE; UTRAN Routing Area in UMTS; or Tracking Area in LTE when it has been determined that the system information of the target cell has been collected. 
     
     
       37. The wireless device of  claim 36  further comprising means for starting to monitor the at least one paging channel in the target cell. 
     
     
       38. The wireless device of  claim 33  further comprising means for checking for a page in the source cell at the scheduled times. 
     
     
       39. The wireless device of  claim 38  further comprising means for answering the page in the source cell. 
     
     
       40. The wireless device of  claim 38  further comprising means for determining that the quality of the source cell is above a threshold. 
     
     
       41. The wireless device of  claim 40  further comprising means for answering the page in the source cell if when it has been determined that the quality of the source cell is above the threshold. 
     
     
       42. The wireless device of  claim 40  further comprising means for performing a mobility information update on the target cell when it has been determined that the quality of the source cell is not above the threshold. 
     
     
       43. The wireless device of  claim 42  further comprising means for answering the page in the target cell. 
     
     
       44. The wireless device of  claim 40  wherein the threshold is a value of one of the following: a received signal level, a received signal-to-noise ratio, a received interference power, a total received power, a path loss, a bit error rate, a frame error rate or a packet loss rate. 
     
     
       45. The wireless device of  claim 33  further comprising means for comparing a target cell signal quality with a source cell signal quality to determine triggering the inter-radio access technology (IRAT) transition. 
     
     
       46. The wireless device of  claim 33  wherein the source cell is within a 2G coverage area and the target cell is within a 3G coverage area. 
     
     
       47. The wireless device of  claim 33  wherein the source cell is within a GSM coverage area and the target cell is within a LTE coverage area. 
     
     
       48. The wireless device of  claim 33  wherein the source cell is within a GSM/GPRS/EDGE coverage area and the target cell is within a UMTS coverage area. 
     
     
       49. A computer program product, comprising: a computer-readable medium including program codes stored thereon, comprising:
 program codes for causing a computer to trigger an inter-radio access technology (IRAT) transition from a source cell to a target cell; 
 program codes for causing the computer to store information regarding scheduled times of a plurality of paging occasions in the source cell; and 
 program codes for causing the computer to check, at the scheduled times, at least one paging channel in the source cell during transition to the target cell and before starting to monitor at least one paging channel in the target cell. 
 
     
     
       50. The computer program product of  claim 49  further comprising program codes for causing the computer to collect system information of the target cell to allow successful inter-radio access technology transition. 
     
     
       51. The computer program product of  claim 50  further comprising program codes for causing the computer to determine that the system information of the target cell has been collected. 
     
     
       52. The computer program product of  claim 51  further comprising program codes for causing the computer to perform a mobility information update on the target cell including one or more of Location Area update in GSM, GPRS, UMTS or LTE; Routing Area update in GPRS, UMTS or LTE; UTRAN Routing Area in UMTS; or Tracking Area in LTE when it has been determined that the system information of the target cell has been collected. 
     
     
       53. The computer program product of  claim 52  further comprising program codes for causing the computer to start to monitor the at least one paging channel in the target cell. 
     
     
       54. The computer program product of  claim 49  further comprising program codes for causing the computer to check for a page in the source cell at the scheduled times. 
     
     
       55. The computer program product of  claim 54  further comprising program codes for causing the computer to answer the page in the source cell. 
     
     
       56. The computer program product of  claim 54  further comprising program codes for causing the computer to determine that the quality of the source cell is above a threshold. 
     
     
       57. The computer program product of  claim 56  further comprising program codes for causing the computer to answer the page in the source cell when it has been determined that the quality of the source cell is above the threshold. 
     
     
       58. The computer program product of  claim 56  further comprising program codes for causing the computer to perform a mobility information update on the target cell when it has been determined that the quality of the source cell is not above the threshold. 
     
     
       59. The computer program product of  claim 58  further comprising program codes for causing the computer to answer the page in the target cell. 
     
     
       60. The computer program product of  claim 49  further comprising program codes for causing the computer to compare a target cell signal quality with a source cell signal quality to determine triggering the inter-radio access technology (IRAT) transition.